Conventionally, when supplying a gas-fuel, such as LPG and CNG, to an engine, a high pressure gas-fuel liquidized and contained in a pressure container is depressurized by a regulator to a pressure as low as the atmospheric pressure, and the gas-fuel is supplied to a mixer or an injector and then to a gas engine via a suction pipe.
Pressure governing control on a gas-fuel by the regulator is disclosed, for example, in JP 2003-232265 A. As illustrated in FIG. 6, a valve 5 is provided at a fuel inlet 4 leading to a pressure adjusting chamber 3 which is separated by a diaphragm 2 from a back pressure chamber 1 communicating with the atmosphere, and a control-pressure adjusting spring 6 is provided to push the diaphragm 2 against the atmospheric pressure in the back pressure chamber 1. Back and forth displacements of the diaphragm 2 are transmitted by a valve lever 8 pivotally supported by a pin 7 to open and close the valve 5, and thereby the pressure is controlled.
As illustrated in FIGS. 7 and 8, the valve 5 of the gas-fuel-supply regulator includes a sleeve-like valve base 52 provided at the outlet of the fuel inlet 4 and having a rim on a top-opening that serves as a valve seat 51, and a disk-shaped valve body 54 that has a seating face 53 and closely seats on the valve seat 51. After the leakage rate adjusted for each product assembly, the valve body 54 is supported on the valve lever 8, which is pivotally supported by the pin 7 at a location close to the valve base 52, via a supporting member 9 bonded with an adhesive 82 to the valve lever 8.
This structure is however disadvantageous in that, by reassembly or replacement of the valve body 54, the pre-adjusted relative relationship between the valve body 54 and the valve base 52 may be lost and thus a specified sealing performance may not be maintained.
As a conventional solution to this problem, as illustrated in FIG. 8, for example, a valve 5 is proposed that includes a supporting member 9 having a semispherical bottom portion that contacts the valve body 54 in a manner allowing the relative motion of the valve body 54 to the supporting member 9 (the connected valve body 54 being allowed to pitch in any direction about the center of the valve body 54). The valve 5 adjusts by itself the tilt of the valve body 54, moved by the valve lever 8, to the valve base 52.
The self-adjusting valve 5 however is disadvantageous under a small opening of the valve body 54, that is, in a minimal flow rate range, where unstable seating of the valve body 54 deteriorates controllability of the valve 5 under a minimal pressure and the free motion of the valve body 54 causes unstableness and reduces reliability.